Development of reusable palladium catalysts supported on hydrogen titanate nanotubes for the Heck reaction

Martínez-Klimov, Mark E.; Hernández-Hipólito, Patricia; Klimova, Tatiana; Solís-Casados, Dora Alicia; Martínez‐García, Marcos

doi:10.1016/j.jcat.2016.07.019

Cited by 34 publications

(12 citation statements)

References 42 publications

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“…In the XPS analysis, the low intensity bands at 336.5 and 341.9 eV were attributed to palladium oxide, [ 32–34 ] whereas the intensity band at 338.5 and 343.8 eV were attributed to trace Pd (OAc) 2 . [ 35 ] Using the collected fresh palladium black as catalyst for benzyl alcohol oxidation in the next run disclosed that no benzaldehyde was detected in analysis, thus confirming that the generated palladium black was inactive in this reaction. In the case of using the palladium oxide instead of Pd (OAc) 2 as catalyst, also no benzaldehyde product was obtained.…”

Section: Resultsmentioning

confidence: 91%

Palladium (II)‐catalyzed homogeneous alcohol oxidations: Disclosing the crucial contribution of palladium nanoparticles in catalysis

Zhang

Lou

Xue

et al. 2020

Applied Organom Chemis

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Versatile redox catalysts play the significant roles in alcohol oxidations, in which the mechanisms for homogeneous and heterogeneous alcohol oxidations are generally different. This work introduced a Lewis acid (LA) promoted homogeneous alcohol oxidation with Pd (OAc)2 catalyst by using oxygen balloon as the oxidant source. It was found that adding Lewis acid such as Sc (OTf)3 significantly accelerated Pd (II)‐catalyzed alcohol oxidations; notably, the time courses of oxidations monitored by GC and 1H NMR disclosed that there existed two processes including the initial sluggish oxidation followed by a rapid oxidation. The promotional effect of Lewis acid was attributed to the formation of heterobimetallic Pd (II)/LA species, which improved the oxidizing power of the palladium (II) species, thus accelerating alcohol oxidation in the induction period. Correlating the sizes of in situ generated palladium nanoparticles with the time course of alcohol oxidation further disclosed that the loosely, spherically large nanoparticles, which were composed of many tiny nanoparticles having the size less than 10 nm, were responsible for the rapid oxidation, whereas those highly dispersed, tiny nanoparticles having the size less than 10 nm were not responsible for the rapid oxidation.

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Section: Resultsmentioning

confidence: 91%

Palladium (II)‐catalyzed homogeneous alcohol oxidations: Disclosing the crucial contribution of palladium nanoparticles in catalysis

Zhang

Lou

Xue

et al. 2020

Applied Organom Chemis

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“…The standard deviation in the binding energy (BE) values was +0.l eV. The high-resolution narrow-scan spectra obtained were smoothed and fitted using the Gaussian functions of the origin 92E software [62].…”

Section: Physico-chemical Characterization Of the Supporting Materialsmentioning

confidence: 99%

Development of an Adsorbing System Made of DMS-1 Mesh Modified by Amino Groups to Remove Pb(II) Ions from Water

et al. 2020

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Water pollution by heavy metals represents several health risks. Conventional technologies employed to eliminate lead ions from residual or drinking water are expensive, therefore an efficient and low-cost technique is required and adsorption processes are a good alternative. In this work, the goal was to determine the adsorption capacity of a Disordered Mesoporous Silica 1 material (DMS-1) functionalized with amino groups, for Pb(II) ions removal. DMS-1 was prepared by sol-gel method and the incorporation of amino groups was performed by ex-situ method. As the source of amine groups, (3-Aminopropyl) triethoxysilane (APTES) was used and three different xNH2/DMS-1 molar ratios (0.2, 0.3, 0.4) were evaluated. In order to evaluate the incorporation of the amino group into the mesopore channels, thermal and structural analysis were made through Thermogravimetric Analysis (TGA), nitrogen adsorption–desorption at 77 K by Specific Brunauer–Emmett–Teller (SBET) method, Fourier Transfer Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and X-Ray Photoelectron Spectroscopy (XPS). The higher Pb(II) ions removal was achieved with the 0.3 molar proportion of xNH2/DMS-1 reaching 99.44% efficiency. This result suggests that the functionalized material can be used as an efficient adsorbent for Pb(II) ions from aqueous solution.

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“…To suppress the Pd aggregation, many nanostructured inorganic and organic supports modi ed with N-, S-and P-containing groups have been developed to stabilize the active Pd species through enhancing the metal-support inter-actions 19,20 . However, these approaches mainly focused on the control of the Pd aggregation over the catalyst surface, and the Pd aggregation in solution has not been effectively prohibited, which still inevitably led to a remarkable deactivation and frustrated recyclability although these Pd aggregates could be redeposited onto the catalyst surface 10,11,[21][22][23][24][25][26] . Thus, the development of a novel support, which can not only e ciently recapture the dissolved Pd before their aggregation in solution but also stabilize the resupported Pd species during the redeposition process, is highly desired to improve the stability of the supported Pd catalysts.…”

Section: Introductionmentioning

confidence: 99%

Enhancing stability by trapping palladium inside N-heterocyclic carbene-functionalized hypercrosslinked polymers for heterogeneous C-C bond formations

Yue

Xing

Sun

et al. 2020

Preprint

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Catalyst deactivation caused by the aggregation of active metal species in the reaction process poses great challenges for practical applications of supported metal catalysts in solid-liquid catalysis. Herein, we developed a hypercrosslinked polymer integrated with N-heterocyclic carbene (NHC) as bifunctional support to stabilize palladium in heterogeneous C-C bond formations. This polymer supported palladium catalyst exhibits excellent stability in the one-pot fluorocarbonylation of indoles to four kinds of valuable indole-derived carbonyl compounds in cascade or sequential manner, as well as the representative Suzuki-Miyaura coupling reaction. Stabilizing mechanism investigations disclose that this catalyst displays a molecular fence effect in which the coordination of NHC sites and confinement of polymer skeleton contribute together to stabilize the active palladium species in the reaction process. This work provides new insight into the development of supported metal catalysts with high stability and will also boost their efficient applications in advanced synthesis.

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Development of reusable palladium catalysts supported on hydrogen titanate nanotubes for the Heck reaction

Cited by 34 publications

References 42 publications

Palladium (II)‐catalyzed homogeneous alcohol oxidations: Disclosing the crucial contribution of palladium nanoparticles in catalysis

Palladium (II)‐catalyzed homogeneous alcohol oxidations: Disclosing the crucial contribution of palladium nanoparticles in catalysis

Development of an Adsorbing System Made of DMS-1 Mesh Modified by Amino Groups to Remove Pb(II) Ions from Water

Enhancing stability by trapping palladium inside N-heterocyclic carbene-functionalized hypercrosslinked polymers for heterogeneous C-C bond formations

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